Darwin & Natural Selection PDF

chick developement Darwin & Natural Selection  Learning Goals ▪ 1. Define "Evolution" & "Natural Selection". ▪ 2. Describe the 4 steps of Natural Selection, giving an example of each. ▪ 3. Explain the importance of "Variation". ▪ 4. List the 5 evidences that support the Theory of Evol...

chick developement Darwin & Natural Selection  Learning Goals ▪ 1. Define "Evolution" & "Natural Selection". ▪ 2. Describe the 4 steps of Natural Selection, giving an example of each. ▪ 3. Explain the importance of "Variation". ▪ 4. List the 5 evidences that support the Theory of Evolution. Theory of Evolution ▪ Evolution: The process of change over time Specifically, a change in the frequency of a gene or allele in a population over time Charles Darwin ▪ Father of Evolution ▪ Proposed a mechanism for evolution, natural selection ▪ Darwin went on a 5-year trip around the world on the ship, the HMS Beagle As the ship’s naturalist, he made observations of Wrote organisms in South a book, “Origin of the America and the Species” Darwin’s Finches Natural Selection ▪ Natural Selection: Organisms that are best adapted to an environment survive and reproduce more than others  CFU: Plickers The process of change over time is called: a)Natural Selection b)Evolution c) Darwinism d)Trust the process Steps of Evolution ▪ Darwin’s Theory of Evolution occurs in four steps: Overproduction (overpopulation) Competition Variation Survival  CFU: Plickers Which of the following is NOT one of the four steps of evolution: a)overproduction b)variation c)natural selection d)survival 1. Overproduction:Potential for a species to increase in number ▪ Each species produces more offspring that can survive Overpopulation ▪ Negative: having a population so dense as to cause environmental deterioration, an impaired quality of life, or a population crash. ▪ Positive: still large enough population and genetic diversity (variation).  2. Variation: New genetic changes within a species ▪ Each individual has a unique combination of inherited traits. ▪ Adaptation: an inherited trait that increases an organism’s chances of survival Inheritance ▪ Inheritance - The passing of genetic characteristics from parent or ancestor to offspring. ▪ Ex. Traits such as eye color, height, hair color, etc.  CFU: Plickers A genetic change within a species is called: a)Variation b)Overproduction c) Adaptation d)New me What adaptations do you see? What adaptations do you see? What causes members of the same species to be different from one another? ▪ GENETIC VARIATION! Why is Variation Important? ▪ Because the environment changes. ▪ The more variation within a species, the more likely it will survive Ex: If everyone is the same, they are all vulnerable to the same environmental changes or diseases ▪ The more variation of types of species in an habitat, the more  3. Competition: competition for limited resources ▪ Individuals COMPETE for limited resources: Food, water, space, mates ▪ Natural selection occurs through “Survival of the fittest” ▪ Fitness: the ability to survive and reproduce ▪ Not all individuals survive to adulthood  CFU: Plickers The ability to survive and reproduce is called: a)Natural Selection b)Competition c) Survival of the fittest d)law of the jungle 4. Survival: Proliferation of those organisms that are better able to survive and reproduce in the environment ▪ The individuals with the best traits / adaptations will survive and have the opportunity to pass on it’s traits to offspring. Natural selection acts on the phenotype (physical appearance), not the genotype (genetic makeup) Ex: When a predator finds its prey, it is due to the prey’s physical characteristics, like color or slow speed, not the alleles (BB, Bb)  CFU: Plickers Phenotype is the: a)physics b)physical appearance c) genetic makeup d)DNA code  Peppered Moth A ▪ Which moth will the bird catch? B ▪ Stop Point – Natural Selection ▪ http://www.hhmi.org/biointeractive/ making-fittest-natural-selection-an d-adaptation Evidence for Evolution: ▪ Fossil Record ▪ Homologous Body Structures ▪ Vestigial Organs ▪ Embryology ▪ Biochemical Evidence The Fossil Record ▪ Fossils: a record of the history of life on Earth Homologous Body Structures ▪ Homologous Body Structures: similar anatomy in different types of animals because of common ancestor Vestigial Organs Vestigial Organs: “leftover” traces of evolution that serve no purpose Embryology ▪ Embryology: embryos of all vertebrates are very similar early on Biochemical Evidence ▪ Biochemistry: DNA with more similar sequences suggest species are more closely related EX: Humans and chimpanzees share more than 98% of identical DNA sequences  Learning Goals ▪ 1. Define "Evolution" & "Natural Selection". ▪ 2. Describe the 4 steps of Natural Selection, giving an example of each. ▪ 3. Explain the importance of "Variation". ▪ 4. List the 5 evidences that support the Theory of Evolution. Coral Snake Milk Snake (Poisonous) (Not poisonous) Stick Mantid Flower Mantid